
var result_1;

alert(1);
//加法
function add()
{
    
    var a=getFirstNumber();
    var b=getSecondNumber();
    result_1=Number(a)+Number(b);
    sendNumber(result_1);
    
}



function getFirstNumber()
{
    return  document.getElementById('first');
}

function getSecondNumber()
{
    return document.getElementById('twice').value;
    
}

function sendNumber(result_1 )
{
    document.getElementById('result').innerHTML=result_1;
    
}


